A bid by a Swedish company to be the first in the United States to display weaker warnings on its tobacco product suffered a blow on Friday when a panel of experts convened by the Food and Drug Administration concluded that the proposed label did not fully convey the product’s health risks.

The company, Swedish Match, argues that its product, Snus (pronounced snoose) — moist ground tobacco in a sachet to be tucked between the lip and the gum — is far less harmful than cigarettes and that any warning label should reflect that. The company argued that the current rules, which treat all tobacco products as equally dangerous, are misleading and a disservice to the more than 40 million Americans who still smoke.

But the panel of outside experts did not see it that way. Experts repeatedly said more studies were needed before they could be sure such a change was justified for a tobacco product. They said that the research the company presented did not rule out certain health risks, such as adverse effects in pregnancy, and that the proposed label did not reflect that.

One panel member said there also was not enough information on the environmental impact — for example, on how the used sachets would be disposed of.

The panel’s recommendations are not binding, but opponents of smoking said the F.D.A. would be hard pressed to approve the company’s application after the tough treatment at the meeting.

“F.D.A. will have no choice but to reject Swedish Match’s application,” said Matthew Myers, president of the Campaign for Tobacco Free Kids, an antismoking group.

But Dr. Lars-Erik Rutqvist, senior vice president of scientific affairs for Swedish Match, sounded an optimistic note, pointing out that such panels are designed to be critical and that the F.D.A. is not obligated to take their advice.

The agency has until June to rule on the company’s application.

“If you ask me, ‘Are you depressed?’ I say no,” he said, sitting at a table in a carpeted conference room at the F.D.A.’s sprawling facility in suburban Maryland. “The role of this committee is to pick apart the type of material they are being presented with, and they did a good job of that.”

It is the first time since the government began requiring warning labels 50 years ago that federal regulators are considering whether to let a company claim a tobacco product is less harmful than cigarettes.

Swedish Match says that Snus is 90 percent less harmful than cigarettes and argues that the product’s popularity in Sweden helped drive rates of lung cancer and oral cancer in men to the lowest levels in Europe. The company submitted more than 130,000 pages of documents, hoping to prove the claims, including dozens of studies and 50 years of data from Snus users in Sweden.

The panel’s meeting stretched over two days and included 10 voting questions, but the tone tilted decidedly against the company.

The panel was not asked directly whether the F.D.A. should approve Swedish Match’s application, but was tasked with evaluating whether the evidence presented justified a gentler label.

Panel members voted unanimously that the evidence was insufficient to prove that Snus did not increase the risk of tooth loss or gum disease, though they were split on whether there was evidence that showed any increased risk of oral cancer.

Perhaps the most direct question, whether the research showed that health risks from Snus were “substantially lower” than those from cigarettes, divided the panel in half, with four members voting yes and four no.

“I voted no because I have a problem with the word ‘substantially’ lower as it relates to all health risks,” said Pebbles Fagan, an associate professor at the University of Hawaii Cancer Center. “There’s no evidence that pregnancy outcomes related to Snus would be any different than with any other tobacco product.”

But other panel members were persuaded.

“You can still care about a wide array of health effects and still endorse the idea that there’s a substantial reduction in risk,” said Kurt M. Ribisl, a professor of health behavior at the University of North Carolina Gillings School of Global Public Health. “Cancer and heart disease are top killers of women in this country, and the risk for those are substantially lower in these products.”

Some experts cautioned that being too strict could backfire, preserving the status quo, which offers addicted smokers very few appealing options for quitting.

“The evidence is very strong over decades that this product is substantially lower in risk when compared with cigarettes,” said David Abrams, executive director of the Schroeder National Institute for Tobacco Research and Policy Studies at the Legacy Foundation, an antismoking research group, adding that authorities should keep close tabs on use by youth. “This bigger picture should not be missed.”

The debate often lagged, and committee proceedings were punctuated by long silences, prompting one member to remark that “sitting here silently” was not going to help the agency decide.

At one point Mitch Zeller, head of the F.D.A.’s Center for Tobacco Products, which will ultimately decide on the application, appealed directly to the members. “It is not an easy question we put to you, but we do need you to grapple with it and ultimately render a vote,” he said.

Mr. Zeller congratulated the company as the meeting ended, calling it a “trailblazer.”

A version of this article appears in print on , on Page A12 of the New York edition with the headline: Milder Warning Opposed for Swedish Tobacco Item. Order Reprints | Today’s Paper | Subscribe